Title:Effects of Overlapping Strings in pp Collisions

Abstract: In models for hadron collisions based on string hadronization, the strings
are usually treated as independent, allowing no interaction between the
confined colour fields. In studies of nucleus collisions it has been suggested
that strings close in space can fuse to form "colour ropes". Such ropes are
expected to give more strange particles and baryons, which also has been
suggested as a signal for plasma formation. Overlapping strings can also be
expected in pp collisions, where usually no phase transition is expected. In
particular at the high LHC energies the expected density of strings is quite
high. To investigate possible effects of rope formation, we present a model in
which strings are allowed to combine into higher multiplets, giving rise to
increased production of baryons and strangeness, or recombine into singlet
structures and vanish. Also a crude model for strings recombining into junction
structures is considered, again giving rise to increased baryon production. The
models are implemented in the DIPSY MC event generator, using PYTHIA 8 for
hadronization, and comparison to pp minimum bias data, reveals improvement in
the description of identified particle spectra.